Firewalling is more granular at the application behavior level. This is good news, and I'll be interested in trying it out to see how much control we will get.

Stronger disk encryption - AES 256 is now supported for those with high encryption requirements.

There are a number of other security features included. Time Machine, Apple's automatic backup and versioning system may be the most interesting for security analysts, as it may preserve data that users or attackers believe that they have removed from the system.